1. Field of the Invention
The present invention relates to an image display system including an image display apparatus which allows an observer to observe a stereoscopic image by using the parallax between the right and left eyes of the observer and a control apparatus for controlling the display apparatus, and a control method therefor and, more particularly, to an image display system for providing an operation environment for comfortable stereoscopic display, an image display apparatus and an information processing apparatus in the system, and a control method and a storage medium used in the apparatuses.
2. Related Background Art
A lenticular scheme and a parallax barrier scheme have been proposed as schemes for stereoscopic image display apparatuses using neither shutter glasses nor polarization glasses. In these apparatuses, special optical elements such as lenticular lenses and parallax barriers are generally placed on the front surface sides of display devices. These special optical elements are relatively inexpensive and exhibit high productivity. A simple stereoscopic image display apparatus can be easily constituted by a combination of such an optical element and a 2D display. These schemes are means especially effective for liquid crystal display devices (LCDs) and the like having flat display surfaces.
For example, the parallax barrier scheme is disclosed in S. H. Kaplan, "Theory of Parallax Barriers.", J. SMPTE, Vol. 59, No. 7, pp. 11-21 (1952). According to this scheme, a vertically striped image obtained by alternately arranging at least right and left images of a plurality of parallax images from a plurality of viewpoints into a vertically striped pattern is observed through a slit pattern (called a parallax barrier) having predetermined opening portions placed at a predetermined distance from this image. With this operation, the right and left images of the vertically striped image are independently observed with the right and left eyes. As a result, parallax images corresponding to the right and left eyes are observed with the right and left eyes, thus realizing a stereoscopic view.
Japanese Patent Laid-Open Nos. 3-119889 and 5-122733 disclose stereoscopic display apparatuses in which a parallax barrier is electronically generated by a transmission type liquid crystal display device and the like, and the shape and position of each stripe are variably controlled to improve the compatibility with conventional 2D image display apparatuses.
FIG. 11 shows the basic arrangement of the stereoscopic image display apparatus disclosed in Japanese Patent Laid-Open No. 3-119889. This stereoscopic image display apparatus includes a transmission type liquid crystal display apparatus 11 for displaying parallax images and an electronic parallax barrier 13 constituted by a transmission type liquid crystal display placed on the liquid crystal display apparatus 11 through a spacer 12 having a thickness D. A parallax barrier pattern is displayed on the electronic parallax barrier 13. Note that a stereogram having, for example, right and left parallax images alternately arranged into a vertically striped pattern is displayed on the liquid crystal display apparatus 11. The spacer 12 is made of transparent glass, acrylic resin, or the like.
In this stereoscopic image display apparatus, a vertically striped image consisting of parallax images sensed from two or more directions is displayed on the liquid crystal display apparatus 11, and a parallax barrier pattern is formed at an arbitrary position on the barrier surface of the electronic parallax barrier 13 upon designation of X and Y addresses by a control means such as a microcomputer 14, thereby allowing a stereoscopic view based on the principle of the above parallax barrier scheme.
In this apparatus, when the display of the parallax barrier pattern on the electronic parallax barrier 13 is stopped to make the entire image display area of the electronic parallax barrier 13 colorless and transparent, 2D image display can be performed. The compatibility between 2D display and 3D display is realized in this manner.
An apparatus capable of performing mixed display of 3D and 2D images within a single plane is disclosed in Japanese Patent Laid-Open No. 5-122733. In this apparatus, as shown in FIGS. 12A and 12B, a barrier striped pattern can be generated in the entire area or a partial area of the electronic parallax barrier 13.
When a 3D display capable of performing mixed display of 2D and 3D images is to be used, a system for controlling 2D and 3D display areas in accordance with the needs of the user is required. When the image information generated by a computer is to be displayed, in particular, it becomes necessary to draw several windows on the screen of the display apparatus and selectively set the 2D and 3D display modes in units of windows. No conventional computer systems can serve such a purpose.